1. Field of the Invention
The present invention relates generally to laser systems and more particularly to non-lethal laser weapon systems for dazzling or stunning humans.
2. Description of Related Art
In recent years, military, security and police forces have placed an increasing emphasis on using non-lethal threat deterrence systems to neutralize threats without causing permanent injury to the target being suppressed. Such devices are desirable in a number of circumstances, such as when apprehending violent but unarmed subjects, for crowd control, during cell extractions, and when deadly force poses a risk to innocent bystanders or is otherwise unwarranted by the threat level. Examples of non-lethal weapons include high-voltage “taser” stun guns and chemical irritants such as pepper spray, tear gas, and the like.
It has also been recognized that high-intensity light sources have some threat-deterrence capability. For example, high-intensity light can present a glare that degrades vision, makes it difficult to see the direction of the light source, and causes discomfort while in the visual field of the observer. High-intensity light can also momentarily blind (“flashblind”) the viewer, causing a significant effect on the retinal adaptation level resulting in a loss of visual sensitivity after the light source is removed, and can even promote physiological responses such as disorientation and nausea. The intensity and wavelength of the light, as well as the use of pulsed light, flashing and/or color-changing lights can all influence how the viewer is affected by the light. Generally speaking, these useful deterrent effects are referred to herein as “dazzling” effects.
Lasers, which provide an intense coherent beam of light, have been found to be particularly useful as a high-energy light source that can be used to daze or temporarily blind a subject. However, excessive exposure to laser radiation can cause permanent eye damage and blindness. As such, non-lethal weapons that use laser light sources must strike a balance between being intense enough to obtain the desired dazzling effects, and not being so intense that they cause permanent eye damage to the target.
The American National Standards Institute (ANSI) has developed laser safety guidelines (ANSI Z136.1-1993) that set forth the maximum permissible exposure to laser radiation to prevent permanent eye damage. In general terms, the maximum level of exposure is a function of the laser wavelength, the irradiance (also called the intensity or power density) at the location of the eye, which is typically measured as watts per square centimeter (W/cm2), and the duration of the exposure. For purposes of calculating the exposure duration one typically assumes that the exposure duration is equal to the human blink response, which is about 0.250 seconds.
Based on these principles, a number of non-lethal laser weapon systems have been developed for use in self-defense, crowd control and other threat-deterrence situations. Examples of such devices are shown in U.S. Pat. Nos. 6,142,650 and 6,431,732 to Brown et al. and U.S. Pat. No. 6,190,022 to Tocci et al., which are incorporated herein by reference. These hand-held devices generally focus one or more lasers or high-intensity diode lasers or lights into a single collimated light source, and incorporate this light source into a conventional flashlight-like structure. These devices suffer from a significant drawback in that the collimated light beam must diverge rapidly to prevent it from being too intense at short distances, which has the result of making the device effective only over relatively short distances. Other performance aspects and drawbacks of such devices are discussed in Air Force Research Laboratory Report Number AFRL-HE-BR-TR-2001-0095, dated May, 2001 and titled “Visual Effects Assessment of the Green Laser-Baton Illuminator (GLBI),” which is incorporated herein by reference.
Therefore, an objective of the present invention is to provide an improved laser dazzling system that provides effective long- and short-range dazzling effects. Although certain deficiencies in the related art are described in this background discussion and elsewhere, it will be understood that these deficiencies were not necessarily heretofore recognized or known as deficiencies. Furthermore, it will be understood that, to the extent that one or more of the deficiencies described herein may be found in an embodiment of the claimed invention, the presence of such deficiencies does not detract from the novelty or non-obviousness of the invention or remove the embodiment from the scope of the claimed invention.